Negotiators in Paris are trying to craft a deal at the UN climate talks that will keep global temperature rise below 2C. But what does that mean in reality - and what difference will a couple of extra degrees really make?

Ice broken off from Perito Moreno glacier floats in Los Glaciares national park, part of the Southern Patagonian Ice Field, the third largest ice field in the world, in Santa Cruz, Argentina. Most glaciers in the park have been retreating over the past 50 years due to global warming.
Photograph: Mario Tama/Getty Images

With over 5C of warming, 12 billion people would be exposed to heatwaves each year, 7.6 million sq km of cropland will decline, 120 million people a year will be affected by flooding, and 2 billion people will be exposed to increased water stress.